Stabilized rosin size and a method of stabilizing the same



I age.

United States Patent STABILIZED ROSIN SIZE AND A METHOD OF STABILIZINGTHE SAME Gerald I. Keim, Oxford, Pa., assignor to Hercules PowderCompany, Wilmington, Del., a corporation of Delaware No Drawing.Application August 2.1, 1953, Serial No. 375,828

4 Claims. (Cl. 106-438) This invention relates to paste rosin sizesstabilized against crystallization and to methods of preparing the same.

Ever since Wurster in 1878 concluded that the prime sizing agent wasfree rosin thrown down by the alum, much stress has been laid on the useof sizes high in free rosin, i. e., having a high acid number. Also, lowfree rosin paste sizes are usually badly gelled and have highviscosities. Such sizes are very difiicult to unload from tank cars orpump from storage. Increasing the free rosin content reduces gel andviscosity. Furthermore, to reduce freight costs and facilitate storageit is desirable to prepare the paste rosin size with as high a solidscontent as possible. Thus, the paste rosin size most desired by the artmust have (1) a high free rosin content (as evidenced by acid number)and (2) a high solids content. Unfortunately paste rosin sizes meetingthese require ments are subject to extensive crystallization duringstor- This crystallization is extremely troublesome causing serious lossof size and plugging of pipe lines when transferring size from drums ortank cars to storage tanks and when removing the size from the storagetanks for use.

The crystalsformed in high free rosin paste sizes consist of a doublesalt of abietic acid and sodium abietate. In paste rosin sizes of highsolids content, i. e., 70% or higher, the crystals consist almostentirely of a 1:1 mixture of abietic acid and sodium abietate, called1:1 salt. As the solids content is lowered below 70% the crystalscontain an appreciable amount of 3:1 salt (three moles of abietic acidfor one mole of sodium abietate), although even at such low solidscontent the crystals most commonly found are 1:1 salt.

The prior art discovered that condensation products of formaldehyde withvarious amines, such as aniline, diethanolamine, morpholine, etc., wereactive in preventing crystallization of 3:1 salt. Such condensationproducts, however, are relatively ineffective to prevent crystallizationof 1:1 salt, particularly at high solids content, i. e., above 70%.Moreover, even at lower solids contents, i. e., 70% and below, thesecondensation products are relatively ineffective for preventingcrystallization of either 3:1 or 1:1 salt in the presence of seedcrystals. Most commercial equipment used for transportation and storageof paste rosin size will contain such seed crystals.

It has now been discovered that crystallization is strikingly inhibitedin paste rosin sizes by the inclusion therein of a stabilizing amount ofthe condensate obtained by reacting a material selected from the groupconsisting of rosin acids, esters of rosin acids, alcohols produced bythe reduction of the carboxyl groups of a rosin acid and esters of saidalcohols, containing two ethylenic double bonds in the rosin nucleuswith a monoether, monoester or ether-ester of a gcm-diol or with agem-diether or gem-diester wherein the oxygen atoms are attached toacyclic carbon atoms. Particularly preferred is the reaction product ofa rosin acid with dimethoxymethane. These condensates together with anovel process for pro- 2,776,905 Patented Jan. 8, 1957 ducing them arefully set forth in the copending application of Alfred L. Rummelsburg,Serial No. 264,241, filed December 29, 1951, now U.- S. Patent No.2,720,513. The compounds whichhave been found useful to inhibitcrystallization in paste rosin sizes in accordance with this inventionare limited to those condensates described in the aforesaid patent ofAlfred L. Rummelsburg. The compounds which are reacted with a rosin acidor rosin acid derivative have the general formula wherein R1 and R2 arehydrogen, alkyl, aryl, aralkyl or alkaryl radicals and may be the sameor different. R3 is an alkyl, aralkyl or acyl group, and R4 is hydrogen,alkyl, aralkyl, or acyl. Representative compounds which may be used inaccordance with this invention are: formals such as dimethoxymethane,dibutoxymethane, acetals such as 1,1-dimethoxyethane, propionals,butyrals, hemiformals such as methyl hemifonnal, hemiacetals,ether-esters of gem-diols such as l-methoxy-l-acetoethane, gem-diesterssuch as ethylidene diacetate, allylidene diacetate, etc. The condensatesdescribed by Rummelsbnrg are operable in the process of the instantinvention whether the condensates are produced by the novel process ofRummelsburg or by somealternative process.

By stabilizing amount is meant a relatively small amount sufficient toprevent excessive crystallization in the paste rosin size during itsstorage under ordinary commercial conditions. Ordinarily, I find thatfrom about 1% to about 10% of condensate, based on the weight of therosin, is sufficient as a crystallization inhibitor when the condensatecontains about one mole of rosin or rosin derivative to about one moleof the monoether, monoester or ether-ester of a gem-diol or with agem-diether or gem-diester wherein the oxygen atoms are attached toacyclic carbon atoms. My preferred range isfrom 1% to 5%. may be used togive a crystallization inhibitor containing progressively smalleramounts of condensate. case, a correspondingly larger amount of theinhibitor is needed to keep thev concentration of condensate within Ifdesired, one may even react a the desired range. suflicient amount ofthe monoether, etc., to form exactly the desired stabilizing amount ofcondensate in situ in the rosin.

The following examples are presented in illustration but not inlimitation of the invention. All parts and percentages are by weightunless otherwise specified.

All of the paste rosin sizes evaluated in the following examples wereprepared as follows: The rosin furnish or fortified rosin furnish wasmelted under a nitrogen blanket and heated to 160 C. In those ex amplcswherein a crystallization inhibitor was used, the inhibitor was blendedwith the rosin furnish at this point. To the molten rosin was then addeda hot soda ash solution containing the calculated quantity of soda ashto neutralize the desired percentage of the rosin furnish. The degree ofsaponification is indicated in the particular examples by setting forththe acid numbers of the resulting sizes. The mix was then stirredmechanically and heated until the reaction was essentially completed.Then the solids were adjusted to give a total solids of about The pasterosin sizes were then seeded with crystals of 1:1 salt and stored in anoven at 60 C. The samples were tested every two or three days to observecrystal formation. The reaction product of rosin and dimethoxymethaneused in the examples was prepared as set forth in Example 1 of theabove-mentioned application of Alfred L. Rummelsburg.

It is evident that more than one mole of rosin Inthis 3. EXAMPLES I AND2 The reaction product of rosin and dimethoxymethane was evaluated inthese examples as a crystallization inhibitor in a very high freerosinsize. The results are set forth in thefollowing table:

Table I Percent Crystallization Acid Days Example Inhibitor NumberStored Amount of Crystallization Based on of the atoll" C.

Rosin Size 1 ..i 52 4 Very heavily crystallized. 2 10 52 60 Very fewcrystals.

Table II 1 Percent i Crystah y lization Acid Days Exmuple [InhibitorNumber Stored Amount of Crystallization Based on of the at 60 C. RosinSize 1 1 3 26. 5 41 No crystals.

5 27.3 41 Do. hi 0 31. 0 1 41 Numerous crystals.

5 35.0 I 41 Very few crystals. 7 n, 0 36. 2 41 Very badly crystallized.8 5 43. 0 41 Mtotlierate amount of crys a s. 9 ..l 0 4.5. 5 41crystallized solid.

From these examples it can clearly be seen that the quantity ofcrystallization inhibitor required depends heavily on the free acidityof the size. The examples show that the crystallization inhibitors ofthe instant invention are effective to inhibit crystallization in pasterosin sizes having as high a total solids as 80% even when the pasterosin size has been seeded with 1:1 salt.

The term paste rosin sizes as used herein refers, of course, to pastesizes made from either wood rosin or gum rosin.

I claim:

1. A method of stabilizing paste rosin sizes against crystallizationwhich comprises incorporating therein stabilizing amounts of acrystallization inhibitor comprising the product obtained by reacting amaterial selected from the group consisting of rosin acids, esters ofresin acids, alcohols produced by the reduction of the carboxyl group ofa rosin acid and esters of said alcohols, containing two ethylenicdouble bonds in the rosin nucleus with a compound of the groupconsisting of monoethers, monoesters and ether-esters of gem-diols; andgem-diethers and gem-diesters wherein the ether and ester oxygen atomsare attached to acyclic carbon atoms.

2. A method of stabilizing paste rosin sizes against crystallizationwhich comprises incorporating therein stabilizing amounts of' acrystallization inhibitor comprising the reaction product of a rosinacid and dimethoxymethane.

3. A paste rosin size composition stabilized against crystallization bythe incorporation therein of stabilizing amounts of a crystallizationinhibitor comprising the reaction product of a compound selected fromthe group consisting of rosin acids, esters of rosin acids, alcoholsproduced by the reduction of the carboxyl group of a rosin acid andesters of said alcohols, containing two ethylenic double bonds in therosin nucleus with a compound of the group consisting of monoethers,monoesters and ether-esters of gem-diols; and gem-diethers and gemdiesters wherein the ether and ester oxygen atoms are attached toacyclic carbon atoms.

4. A paste rosin size composition stabilized against crystallizationbythe incorporation therein of a stabilizing amount of a crystallizationinhibitor comprising the reaction product of a rosin acid anddimethoxymethane.

References Cited in the file of this patent UNITED STATES PATENTS2,294,726 Dreshfield Sept. 1, 1942 2,362,973 Cassaday Nov. 21, 19442,438,096 Poor et a1 Mar. 16, 1948 2,684,300 Wilson et al. July 20, 1954

3. A PASTE ROSIN SIZE COMPOSITION STABILIZED AGAINST CRYSTALLIZATION BYTHE INCORPORATION THEREIN OF STABILIZING AMOUNTS OF A CRYSTALLIZATIONINHIBITOR COMPRISING THE REACTION PRODUCT OF A COMPOUND SELECTED FROMTHE GROUP CONSISTING OF ROSIN ACIDS, ESTERS OF ROSIN ACIDS, ALCOHOLSPRODUCED BY THE REDUCTION OF THE CARBOXYL GROUP OF A ROSIN ACID ANDESTERS OF SAID ALCOHOLS, CONTAINING TWO ETHYLENE DOUBLE BONDS IN THEROSIN NUCLEUS WITH A COMPOUND OF THE GROUP CONSISTING OF MONOETHERS,MONOESTERS AND ETHER-ESTERS OF GEM-DIOLS; AND GEM-DICTHERS ANDGEMDIESTERS WHEREIN THE ETHER AND ESTER OXYGEN ATOMS ARE ATTACHED TOACYCLIC CARBON ATOMS.